1. Field
One embodiment of the invention relates to a disk device having a disk for use as a recording medium and a method of assembling the same.
2. Description of the Related Art
In recent years, disk devices, such as magnetic disk devices, optical disk devices, etc., have been widely used as external recording devices of computers or image or music recording/reproducing apparatuses.
For example, a magnetic disk device generally comprises a spindle motor, magnetic head, carriage assembly, and voice coil motor (VCM). The spindle motor rotates a magnetic disk for use as a recording medium. The magnetic head serves to record and reproduce information to and from the magnetic disk. The carriage assembly supports the magnetic head for movement with respect to the disk. The VCM serves to drive the carriage assembly, thereby moving to and positioning the head in a region over a desired track of the disk.
The spindle motor has a cylindrical hub that serves as a rotor, and a flange is formed on one end side of the hub. The magnetic disk is fitted on the hub and held between a clamper, which is screwed to the upper end of the hub, and the flange of the hub.
Usually, the clamper is formed of a disk-shaped metal plate, which has an abutting portion on its peripheral edge portion that touches the magnetic disk. An aperture for the passage of a screw is formed in the central portion of the clamper. The clamper is provided with a plurality of positioning holes that are situated in positions eccentric to the aperture. The clamper is fixed to the hub of the spindle motor by driving the screw, which is passed through the aperture, into the upper end of the hub and fastening it to the upper surface of the hub, with its peripheral edge portion in contact with the upper surface of the inner peripheral portion of the magnetic disk. As the central portion is fastened by the screw, a flat portion of the clamper is elastically deformed, and a disk clamping force is obtained based on a resulting tensile stress.
Normally, in fixing the clamper to the hub of the spindle motor, the clamper and the hub must be held lest they race. In a conventional magnetic disk device, as described in, for example, Jpn. Pat. Appln. KOKAI Publication No. 2002-343002, therefore, the upper surface of a hub is provided with a plurality of engaging holes corresponding to positioning holes in a clamper. The clamper and the hub are fixed to each other in a manner such that fixing pins are fitted individually into the engaging holes of the hub through the positioning holes of the clamper from above the clamper.
In the conventional magnetic disk device described above, however, the respective positions of the positioning holes, engaging holes, and fixing pins must be all aligned when the clamper and the hub are fixed together, in order to fit the fixing pins into both the positioning holes of the clamper and the engaging holes of the hub. In other words, the respective rotational angles of the individual components must be all coincident when the centers of the components are aligned with a central axis of rotation.
In order to realize such position alignment by the use of an automatic assembly apparatus, for example, it is supposed to be relatively easy to adjust the positional relationship between the clamper and the fixing pins that can be easily handled for alignment with use of a tray or the like. Since the hub is rotatable, however, the positions of the engaging holes are too irregular to be managed practically. Thus, the assembly apparatus requires a function to recognize the positions of the engaging holes of the hub, a hole position alignment mechanism, etc., so that its construction is inevitably complicated and entails an increase in manufacturing cost.